Spock detects an apparent storm, approaching the ship at warp factor 2.6, and concludes that it cannot be a natural phenomenon. The storm bypasses the shields and penetrates the Enterprise. Romaine speaks gibberish and other bridge personnel report various paralysis effects. CaptainKirk characterizes the event as an "attack" and Spock agrees.

In sickbay, Romaine minimizes the event, but DoctorMcCoy insists that Romaine was the most affected of the crew of 430 and he wants to know why. Scott coaxes Romaine to cooperate more fully but Romaine fears her assignment is at risk.

Lieutenant Sulu projects the storm's course as heading for Memory Alpha, which was built without defensive shields in view of its academic purpose. The Enterprise cannot contact Memory Alpha to warn it, nor reach Memory Alpha until the storm has come and gone.

Zetarian victim

Kirk assembles a landing party, annoyed that Scott is dallying in sickbay to tend to Romaine. On Memory Alpha, all the staff is dead except for a female who is making the same garbled sounds Romaine made during the initial "attack" on the bridge.

The female on Memory Alpha dies of "severe brain hemorrhaging due to distortion of all neural systems, dissolution of autonomic nervous system", according to McCoy. The other Memory Alpha personnel have each had a different brain center destroyed.

Kirk interrogates Romaine to try to find a link, but Romaine interrupts the dialogue to urge the crew back to the Enterprise, as she is sure the storm is returning. When Sulu reports the same thing, Kirk orders the landing party back to the ship. The transport of Romaine is interfered with but eventually completed.

Romaine tells Scott she saw the dead workers on Memory Alpha, "in their exact positions." Scott ascribes it simply to "space" and tells Romaine not to report it unless "you want to spend the rest of the trip in sickbay."

As the storm closes, Chekov cannot evade it. Spock reports ten distinct lifeforms in the cloud and doubts that the ship can adequately be shielded against it. The cloud approaches the ship.

Kirk says that "perhaps it understands another kind of language." He orders red alert and for phasers to be fired, first a warning shot, then a shot directly into the cloud. As Sulu reports that the direct shot has slowed the cloud, Kirk orders phaser crews to fire again. But Scott reports by intercom that the damage to the cloud seems to be killing Romaine as well. Kirk orders key personnel to the briefing room.

There, Kirk searches for personal data on Romaine that might relate to the attacking cloud. McCoy reports that two hyperencephalograms show that Romaine's brain wave patterns have been altered since the encounter. Spock thinks McCoy has presented the wrong tape, but his concern shows that the hyperencephalogram now matches the ship's tracking of the cloud. Her mind is joining that of the attacker.

Scott now discloses that Romaine has been seeing future events. Kirk asks Romaine to describe each event. She describes the effects that have occurred, and one that has not occurred: Scott dying.

Kirk orders escape at warp factor 8, but it is useless. He also asks Romaine not to resist but to let the aliens operate through her, hoping to control that moment to save the ship. Finally, he orders the medical lab to prepare antigrav units.

The lights swarm on Romaine and enter her body. Scott despairs that Romaine is lost, and McCoy believes there is no way to force the lights out without killing her. Romaine is determined to retain her identity, but begins speaking for the aliens, which Spock encourages.

The alien reports through Romaine that they are from Zetar, where all humanoid life was destroyed. They are the will of the last hundred from Zetar, who have searched for a millenium "for one through whom we can see and speak and hear and live out our lives."

Kirk insists that Romaine's body "has its own life to lead." The aliens say they regret the killing they have done, but intend to survive. Scott carries Romaine to the pressure chamber. The aliens attack Scott – as Romaine foresaw – but the attack is not fatal. Chamber pressure is increased, despite the risk of killing Romaine. The aliens are driven out of Romaine's body and are gone.

The Enterprise prepares to return to Memory Alpha to let Romaine begin her assignment. In sickbay, Kirk asks his aides for estimates on the incident's permanent impact on her. Spock thinks the episode should strengthen her. Kirk has trouble believing that the aides are, for once, in complete agreement.

Captain's log, stardate 5725.3. The Enterprise is en route to Memory Alpha. It is a planetoid set up by the Federation solely as a central library containing the total cultural history and scientific knowledge of all planetary Federation members. With us is specialist Lieutenant Mira Romaine. She is on board to supervise the transfer of newly designed equipment directly from the Enterprise to Memory Alpha ... When a man of Scotty's years falls in love, the loneliness of his life is suddenly revealed to him. His whole heart once throbbed only to the ship's engines. He could talk only to the ship. Now he can see nothing but the woman.

Captain's log, supplemental, stardate 5725.6. The storm has cleared Memory Alpha. It is heading away at incredible speed. We have been unable to make contact with the planetoid. Its silence is ominous. We are beaming down to investigate.

The co-writer of this episode was ventriloquist and puppeteer Shari Lewis of "Lamb Chop" fame. She was a huge fan of Star Trek and fulfilled a dream by co-writing this episode with her husband Jeremy Tarcher. She also wanted to play Mira Romaine, but was not cast. [1]

When Lewis originally pitched the idea to producer Fred Freiberger, he turned it down, saying that they were already working on a similar concept. When Lewis came back with another story idea, Freiberger told her that he'd buy the first one, because the other similar project had been scrapped.[2]

Lewis wrote the love affair of Scotty into the episode because she thought "Captain Kirk is the one who always gets the girl".[3]

The overhead zoom shot of the bridge in the teaser was not shot for this episode. It apparently was filmed for (but not used in) "The Galileo Seven". Bill Blackburn, rather than Walter Koenig, is at the Navigator station in the shot. It is noticeable that he is wearing Lieutenant stripes in the shot. The crew is also noticeably wearing the velour uniforms seen in season 1 and 2, not the nylon variety that replaced them in season 3.

There is extensive use of Alexander Courage's music from "Where No Man Has Gone Before" in this episode. Most notable is the piece used for the approach of the Zetarians which was scored for the "Where No Man..." scene when the Enterprise encounters the galactic barrier.

This was John Winston's only appearance during Star Trek's final season. It is also the only episode in which he appears in addition to all eight regulars, including Christine Chapel.

Additionally, this is the final episode in which we will see a Tellarite and an Andorian in TOS.

The Human-looking female Memory Alpha technician was originally scripted as being a member of a species known as the "Reidonians". [4]

All the scenes of Mr. Scott while Lt. Romaine is being treated in the chamber in the medical lab show him with a Sciences style chest insignia (with a stylized "globe," as Spock and Dr. McCoy would wear) as opposed to the usual "spiral" on his red duty uniform.

"The Lights of Zetar" was the seventy-second episode of the remastered version of The Original Series to air. It premiered in syndication on the weekend of 7 June2008 and aside from the standard CGI replacement footage of the Enterprise, this episode most notably featured new effects shots of the Zetarians and Memory Alpha, which included the appearance of the library complex, where none had appeared before.

According to Michael Okuda: "Based on the size and spacing of the windows, I'd estimate that each of the domes must be similar to the Superdome." Also, "if you look very closely at the far left dome, you might notice a small blue patch on the top of the dome. That's the Memory Alpha emblem." [5]

The third book in Wallace Moore's "Balzan of the Cat People" pulp SF series, 1975's "The Lights of Zetar," was apparently an homage to this episode.

Star Trek Novel #42, Memory Prime by Gar and Judith Reeves-Stevens, continues the story of Mira on Memory Prime, the successor to Memory Alpha. Other than her romance with Scotty and a very brief mention of the Zetarians, no other story elements are carried over from the episode.

The short story "Ancient History" in the Strange New Worlds VI anthology portrayed Scotty and Captain Morgan Bateson, both catapulted into the future by their respective mishaps, meeting and hashing out, physically and verbally, old rivalries, one of which was based on the fact that Mira Romaine married Bateson after her relationship with Scotty had ended.